1. Field of the Invention
The present invention relates to electric elements and circuits utilizing amorphous oxides. In particular, it relates to semiconductor devices utilizing amorphous oxides.
2. Description of Related Art
In recent years, advance in liquid crystal and ElectroLuminescence (EL) technology brought flat and thin image displaying apparatuses (Flat Panel Display: FPD) into practicalization. These FPDs are driven by an active matrix circuit of an electric field effect type thin film transistor (Thin Film Transistor: TFT) using, for an active layer, amorphous silicon thin film or multi-crystallized silicon thin film provided on a glass substrate.
On the other hand, being after improvement in further thin formation, light weight and destruction resistivity of these FPDs, use of a light and flexible resin substrate instead of a glass substrate is having been tried. However, for manufacturing a transistor using the silicon thin film, comparatively high temperature heating process is required, and in general it is difficult to form it directly onto a resin substrate having low heat resistance. Therefore, development of TFTs using oxide semiconductor thin film with for example ZnO as material that can undergo film deposition at a low temperature is being energetically implemented (Japanese Patent Application Laid-Open No. 2003-298062).
Thus, novel semiconductor devices are expected.